Ethanol inhibits the release of vasopressin from the neural lobe of the rat. The proposed work will use a combined biochemical and electrophysiological approach to determine the mechanisms by which alcohol affects this release. Experiments will be performed on the intact neural lobe, and on a recently-developed preparation of pure neural lobe nerve terminal (neurosecretosomes), in which alcohol produces a similar inhibition of release. If the membrane of the secretosomes is permeabilized with digitonin, ethanol no longer has an effect, suggesting that membrane channels are a target of ethanol. The neurosecretosome is a perfect subject for patch clamp analysis. In the proposed research, patch clamp techniques will be used to correlate EtOH's actions on membrane channels with its effects on release of hormone. In the final pat of the proposal, we will use the electrophysiological and biochemical techniques describe above to examine EtOH's effects on channel activity and hormone release from the NL and from terminals isolated from the NL, in rats selectively greed for particular aspects of alcohol responsivity.